Quenching oil is a cooling medium used in the metal heat treatment process, primarily for quenching, to enhance the physical properties of metals, while also increasing their hardness and strength. It plays a crucial role in the heat treatment process. Not only does it provide the required cooling rate, but it also prevents workpieces from deforming and cracking, ensuring that the workpieces achieve satisfactory hardness and microstructure.
Classification of Heat Treatment Quenching Oils
General Quenching Oil: Offers moderate cooling properties, suitable for general quenching requirements. Ideal for quenching iron alloys with good hardenability, as well as small-sized bearing steel and tool steel components.
Rapid Quenching Oil: Offers quick cooling rates, ideal for workpieces requiring rapid cooling. Suitable for applications requiring high surface hardness and deep hardening layers, such as large and medium-sized steel bearings made of CGr15 and quenching cooling for carburized and carbonitrided materials.
Rapid Bright Quenching Oil: Offers quick cooling speed with excellent brightness retention. Metal parts, after being heated to a certain temperature and cooled in quenching oil, maintain a bright surface, typically used for protective atmosphere quenching.
Vacuum Quenching Oil: Ideal for quenching under vacuum conditions, featuring low saturated vapor pressure and excellent brightness. Used in vacuum quenching processes, it requires low saturated steam pressure and minimal evaporation loss, as well as good thermal stability and cooling capacity. Suitable for vacuum quenching of materials such as bearing steel, tool steel, and medium to large aviation structural steel.
Isothermal Segregation Quenching Oil: Ideal for workpieces requiring controlled cooling processes, such as precision parts and parts prone to deformation. This involves placing the heated workpiece into a quenching medium, ensuring the transformation of the martensite microstructure is completed entirely during the isothermal phase.
High-Speed Quenching Oil: Faster cooling rate, suitable for high-demand quenching processes, such as auto parts and large components.
Conclusion
Quenching oil is a process oil used as a quenching medium. It is typically based on a secondary hydrogenated paraffin-based lubricant, supplemented with additives such as accelerators, high-temperature antioxidants, and brighteners, which are then vacuum degassed, pulse blended, and manufactured.
Quenching oil for heat treatment is used to rapidly dissipate heat during the heat treatment quenching process, lowering the metal parts to the martensite transformation temperature, thereby achieving a higher hardness of martensite structure and depth of hardening. Simultaneously, it must also accommodate the deformation and cracking of the parts, featuring rapid cooling rates at high temperatures and slower cooling rates at low temperatures, making it suitable for the quenching requirements of high-strength fasteners like alloy steel.
